1. Field of the Invention
Example embodiments of the present invention relate to an organic aluminum precursor and to a method of forming a metal wire using the same. More particularly, example embodiments of the present invention relate to an organic aluminum precursor used for a chemical vapor deposition (CVD) process or a cyclic CVD process and to a method of forming a metal wire using the organic aluminum precursor.
A claim of priority under 35 USC § 119 is made to Korean Patent Application NO. 2005-87508 filed on Sep. 21, 2005, the contents of which are herein incorporated by references in their entirety.
2. Description of the Related Art
In order to fabricate a high speed and large capacity semiconductor device, it is necessary that metal conductive structures that transmit electric signals in the semiconductor device have favorable electrical characteristics.
The metal conductive structures in the semiconductor device are usually formed of aluminum (Al), tungsten (W) or copper (Cu). Aluminum has a lower specific resistance relative to that of tungsten. In addition, an aluminum layer pattern may be formed by a dry etching process unlike a copper layer pattern. Thus, aluminum is widely used to form a conductive structure such as a contact, a plug and a wire.
An aluminum wire is usually formed by a plasma vapor deposition (PVD) process such as a sputtering process. However, as an aspect ratio of a via or a contact hole increases, the formation of the aluminum wire by the PVD process has reached its limit.
As a result, a chemical vapor deposition (CVD) process has been applied to form an aluminum wire. A precursor used in a CVD process includes, for example, trimethyl aluminum (TMA), dimethyl aluminum hydride (DMAH) or triisobutyl aluminum (TIBA).
The above-mentioned precursors have a high vapor pressure, which is consider advantageous because the precursor may be easily deposited by a CVD process. However, the CVD process requires a high temperature of about 250° C. to about 400° C. In addition, the aluminum wire may include impurities such as carbon, thereby increasing an electric resistance.
In order to avoid these problems, a deposition process using a dimethylethyl amine alane (DMEAA) precursor has been studied. The DMEM precursor has a high vapor pressure and is deposited at a temperature of about 100° C. to about 200° C. However, the DMEAA precursor is thermally unstable at a room temperature. Hence, a deposition process using a more stable methyl pirolidine alane (MPA) precursor has been suggested. A method of forming an aluminum wire using the MPA precursor is disclosed in Korean Laid-Open Patent Publication No. 2000-0022650. Although the MPA precursor is more thermally stable than the DMEAA precursor, the MPA precursor is also thermally and chemically unstable at a temperature above about 30° C. Hence, when the MPA precursor is introduced into a chamber by a CVD process, the MPA precursor may remain as particles in the chamber and fall on the aluminum wire during formation of the aluminum wire or after formation of the aluminum wire.